The reason nuclear is unpopular is that it is expensive. It's more expensive than coal and gas typically. It's also very slow to deploy. A decade is nothing. We'll hit 2035 when several countries are planning to be 100% renewable powered in about 13 years. That's not a lot of time to build a meaningful amount of nuclear plants. Nuclear plants coming online recently are not great examples of speedily execution on a tight budget either. Despite this, there are still a quite a few under construction (around 50 world wide). It's their financial performance relative to renewables that determines if we end up with more of them.
The word baseload always comes up in these discussions but its meaning never really gets specified in a very satisfying way. For example in GW needed for how long (i.e. GWH). Having such a number would facilitate a discussion about alternate ways how we would get that power more cheaply. That's not a debate nuclear proponents like having because it focuses attention on poor financial performance of nuclear relative to just about anything else.
The simple reality driving a lot of the decision making is that you simply get more GWH per $ with solar and wind. And not just a little bit; the difference is massive. And you get it much quicker too. And it's far less risky from a political point of view.
So instead of getting say 8GW with a very big nuclear plant costing maybe 30-40 billion and taking two decades to get built and planned with lots of uncertainty around the process, you can have 30-40 GW online two years from now for about the same amount of money. That's based on a price of 5000$/kw for recent offshore wind installations. A couple of hundred GW of wind came online over the last few years. The investments in renewables are massive and for good reasons: it delivers results quickly and prices are trending down.
Offshore wind is actually relatively expensive compared to solar and onshore wind. But also relatively reliable. People put solar on their roofs for less (2-3k/kw) and solar plants are even cheaper but of course less stable sources of power. Add batteries to the mix and other forms of storage (ammonia, hydrogen, thermal mass, pumped hydro, etc.) and there is no lack of a "baseload" that can't be planned for and mitigated. It will have a price and a certain capacity and that's what needs to be debated in Glasgow. It's a conference about allocating massive amounts of money in the next decades. The stakes are high both in financial terms and in the outcomes.
Nuclear might be part of this if the price is right. But the whole nuclear or nothing attitude is just not a very productive argument. Many countries that have the option are still doing some nuclear of course. But far less than what they are allocating for wind and solar (in dollars and planned GWH capacity).